So finally got round to thinking about fitting an aero filler and have a few things to consider. I currently have a Rover Metro cap and it has an aluminium piece (spinner) like this https://caterhamparts.co.uk/fittings/4527-spinning-fuel-filler-neck-rover-plastic-cap-type-100.html held on with six rivets. I am going to drill out the rivets and it appears that the new aero filler will just cover the holes which are 92mm PCD and the new cap they are 80mm PCD so will need to drill new 6mm holes at this diameter. I am assume the new neck fits directly to the panel without the need for anything other than the cork gasket? The old filler neck has three connections and this new one only has two. There is a breather coming from the centre of the tank, see photo below. It seems that the newer injection tanks do not have this extra mid tank breather, not sure why but as mine has this breather I assume it needs to be connected? I can use a T piece to connect it into the main breather but this got me thinking about the one way valve set up.I have one of these one way valves fitted but I am wondering if it is fit for purpose as I am not sure it allows for tank pressure to be relieved, only air to be drawn in? https://www.carbuilder.com/uk/aluminium-non-return-valve-8mm The Caterham Workshop Notice does not seem to say what valve to fit and the only one can see on the Caterham site is this one. https://caterhamparts.co.uk/hoses/761-one-way-valve-filler-neck-to-charcoal-cannister.html I assume this is a two ball version that allows for air to escape but allows air in to the tank and stops fuel escaping. Merlin Motorsport and Demon Tweeks do versions https://www.merlinmotorsport.co.uk/p/roll-over-valve-in-line-with-5-16-8mm-push-on-tails-m-trl88 https://www.demon-tweeks.com/uk/mocal-fuel-tank-pressure-relief-valve-moctpv8/ I am thinking of replacing my Car Builder Solutions valve with one of the two ball variety items. Other than that I thought I may as well replace the main fuel filler pipe and the other fuel pipes as they are 20 years old now. If anyone has any tips/ experience then would be interested in your opinions. Cheers Nick